Field of the Invention
The present invention relates to an exhaust structure for combustion apparatus and a construction method thereof.
Description of the Background Art
In markets, there are locations where an exhaust pipe (a B vent) already placed in a building cannot be removed from a point of view of maintaining appearance of buildings. At such a location, a combustion apparatus can be replaced by introducing a new exhaust tube (a flexible exhaust tube) into the exhaust pipe and an exhaust terminal (a rain cap) which have already been placed.
The technique related to an exhaust pipe of the combustion apparatus is disclosed, for example, in Japanese Patent Laying-Open No. 2000-18566, Japanese Patent Laying-Open No. 2008-82613, and the like. Also, a method for inserting an exhaust tube into an already-placed exhaust pipe is disclosed, for example, in Japanese Utility Model Publication No. 02-47343, Japanese Patent Laying-Open No. 2003-343790 and the like.
When a new exhaust tube is inserted into the already-placed exhaust pipe and exhaust terminal from inside the building, the end of the exhaust tube may come into contact with a ceiling wall of the already-placed exhaust terminal. In this case, the exhaust port of combustion gas in the exhaust tube is blocked by the ceiling wall of the exhaust terminal, which leads to a problem that combustion gas cannot be sufficiently emitted from the exhaust tube.